Cushioned valve tappet



Jan. 4 1927.

J. C. MILLER CUSHIONED VALVE TAPPET Filed April 23, 1 25 WT/VESS:

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v ATTORNEXS.

Patented Jan. 4, 1927.

JACOB C. MILLER, E MILWATl'KEE, WISCONSIN.

CUSHIONED VALVE TAPPET.

Application iiled April 23. 1923. Serial No. 634,144.

The invention relates to the valve tappets of internal combustion engines, and the purpose of the invention is to produce a construction, the use of which will eliminatethe a noise very frequently attendant upon the valve tappets of such engines whennot adjusted with precision.

I attain the purposes of my invention by inserting between the endsv of the divided valve rod, a resilient device designed at all times to maintain contact with the contiguous ends of the said valve rod. The yielding provision incorporated in the said resilient device cushions the blow of the cam upon 1;; the lower end of the valve rod, so that there will be no sudden impact of the meeting ends of the valve rod in the action of such cam. On the contrary, the pressure of the cam is transmitted gradually through the said yielding devices until the limit of their elasticity has been absorbed, and thereafter the thrust of the cam is directed upon the whole of the valve rod.

In a simple form, my invention is em bodiedin a cylindrical shell provided with an interior seat for the spring constituting the resilient means, the said shell being adapted to be seated upon the upper end of the lower section of the valve rod. Guided within the shell with its lower rounded surfacesbearing upon the upper side of the spring, is a step 1n which the lower end of the upper section of the valve rod is seated. A clearance is provided in the shell below the seat 7 for the spring, so that the latter may vibrate within its limits under the impulses of the cam. The spring will possess a sutlicient degree of resiliency to restore the. parts to their normal position and maintain them when. the nose or striking surface of the cam has passed from contact with the lower end of the valve rod.

Means are provided for adjustment, so that any slack or lost motion which may occur between the contiguous ends of the valve rod, may be taken up. As a result. the relations of the parts may .be adjusted with such accuracy as to be in working contact all, of the time, and the thrust on the cam upon the valve rod is so cushioned by the interpositioning of the yielding device in the length of the valve rod, that the knocking or tapping of the meeting ends of the valve red by reason of their sudden impact, is completely eliminated.

the efiective length of the valve rod. But

The novel features of my invention will be pointed out in the appended claim.

In the drawing which accompanies this specification Figure 1 is a vertical sectional view through a valve mechanism constructed in accordance with my invention, part of the valve rod and its head being shown in full lines.

Fig.2 is a vertical section through an im- 5 proved cushioning device, with the parts in normal position.

Fig. 3 is a similar view showing the same parts as positioned under the thrust of the cam.

Fig.4 is a plan view of the shell of my cushioning device, with the circular seat therein, and a spring member forming the resilient element as resting upon the seat in the shaft.

Referring to the drawing, the numeral 10 indicates the upper part of a valve rod and the-numeral 11 the lower part thereof, these parts being aligned and guided for joint movement, as is usual in the type of engines to which the present invention is applied. A rotating cam 12 provided with a nose or striker 13 is adapted to contact with an anti-- friction roll 14, journalled in the lower end of the part 11 of the valve rod, and transmit. the motion of the cam thereto. A confined spring 15, surrounding the upper por- .tion rod 10, serves to seat the valve, when permitted to act upon the withdrawal of the nose or striking point of the cam. ihe upper end of the lower section of the valve rod may be bored and threaded for the reception of a screw 16, adjustable axially with respect to the valve rod, so as to vary other means than those shown may be conveniently used for producing such adjustment.

Seated upon the flat head of the screw 16 is 'a shell 17 which may be conveniently 106 formed as a stamping from a metal disc. The shell is open at its upper end, and is provided at its bottom with an interior circumferential ring, forming a narrow step 18 upon which may rest the outer circular margin of aresilient member 19, of general disc shape. Theresilient'member19 may be comprised of a single element or laminated, as the particular use may require. A step 20 formed as a short cylinder with a Mt rounded lower end 21, is adapted to rest upon the upper face of the resilient member 19, the lower end of the step 20 being provided with a circumferential shoulder 22, to correspond with the depression 23 in the bottom of the shell.

The resilient member 19 is preferably cut away at a plurality of points 24 so as to produce the construction illustrated in Fig. 4, such cut away portions being separated by means of connecting portions or necks 25, which latter are .so designed and proportioned as to cause the resilient member to present a minimum resistance under the pressure of the cam. In assembling the parts, the lower end of the upper section of the valve rod will be set in the step 20, as will be understood from the drawing.

In operation the adjustment desired will be effected through the screw 16, upon which the shell 17 is placed, with the lower end of the part 10 of the, valve rod resting in the step 20, the latter being arranged within the shell in the manner shown. The shell 17 and the step 20 are separated axially of the valve rod by means of the resilient member 19, when the desired adjustment has been made. The apex of the rounded end 21 of the step 20 bears upon the center of the resilient member 19', which latter is supported at its margin upon the step 18 within' the shell. The pressure'of the cam produces a slight telescoping action of the valve rod, which telescoping action is limited by the approach of the circular seat 18 and the circumferential shoulder 22, atwhieh time the resilient member 19 has been flexed to its full extent and in such position acts as a distance piece between the shell 17 and the step 20 preventing their further movement with relation to each other. When the limit of elasticity of the resilient member 19 is thus reached, the two parts of the valve rod move as one under the ,further pressure of the cam. The flexing of the resilient member 19 under-the conditions thus described is very gradual, it commencing at the center of the member 19 at a moment when the resistance is applied, and continuing with an increasing resistance until the limit has been reached and the parts have assumed the relative positions shown in Fig. 3. At such time the further thrust of the cam acts to compress the spring to open the valve.

Upon the withdrawal of the cam from the lower end of the valve rod, the action of the expansion spring 15 quickly seats the valve, thus resisting further movement by the said spring. Thereupon the resilient force of the spring 19 will reverse the telescoping action of the yielding connection and restore the parts to their normal position, as indicated in Fig. 2.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is:

A cushioning device adapted to be inserted in the tappet mechanism of an internal combustion engine, such device comprising a shell and a step sliding therein and a resilient spring, the shell being provided with a seat for supporting .the spring at one side and the step having a rounded end bearing upon the spring at the other side, whereby the telescopic movement of the step within the shell is resisted by a gradually increasing pressure. A

In testimony whereof, I have signed my name at-Milwaukee, this th day of April, 1923.

J. o. MILLER. 

